Carriers won't say much, but they seem to be clearing their shelves of excess smartphone stock that's getting stale by cutting prices for some Windows Phone 8 phones that have been on the market for barely two months.

In one example, AT&T on Thursday said it would begin selling the Samsung ATIV S Neo for $99.99 with a two-year contract starting Nov. 8. The 4.77-in. Neo will be AT&T's first Windows Phone 8 smartphone from Samsung and will run on the carrier's 4G LTE network.

AT&T will also be the exclusive U.S. carrier of the coming Nokia Lumia 1520 with its 6-in. display, also on Windows Phone 8, the carrier revealed earlier this week.

So, are the discounted prices really that significant -- possibly a sign of Windows Phone 8 weakness in the U.S.? Or are the discounts part of a wider pattern caused by having so many smartphones on various platforms with an array of new features hitting the market at the same time?

And why would AT&T begin selling the ATIV S Neo, weeks after rival Sprint did, when a phone's shelf life is considered to be so short?

The answers to these questions are somewhat obscure. To be sure, carriers constantly adjust prices for many smartphones -- especially the slower selling ones --as they recognize that new models, such as the iPhone 5S, will capture buyers' attention of buyers for just a few hurried weeks before year-end sales come to a close.

In such a crowded and fast-paced marketplace, Windows Phone 8 will suffer heavily because it has only 3.3 percent market share, according to research firm Gartner's numbers for the second quarter. Gartner placed Windows Phone 8 third behind phones running the Android mobile operating system and Apple's iOS, but ahead of BlackBerry for the first time.

Analysts theorized that Samsung could be reaching out to AT&T for sales of the ATIV S Neo by offering the carrier some sort of discounted wholesale price to reduce Samsung inventory.

Meanwhile, Sprint's discount on the same phone could be Sprint's way to quickly reduce its own ATIV S Neo inventory. Sprint offered an explanation on Thursday for its Neo discount of 66 percent, indicating concern for its cost-conscious customers. "Sprint is regularly reviewing our product pricing to be sure our offerings are as accessible as possible for our customers," a spokesman said.